Common carotid artery bifurcation levels related to clinical relevant anatomical landmarks / Niveles de Bifurcación de la Arteria Carótida Común en Relación a Puntos de Referencia Anatómicos Relevantes en Clínica

En cirugías de cabeza y cuello, las arterias carótidas comunes son importantes puntos de referencia, para defnir el plano de disección, durante cirugías radicales de cuello. Los objetivos del presente estudio fueron agregar información sobre el diámetro de las arterias carótidas y correlacionar el nivel de bifurcación de la arteria carótida común (ACC) con importantes puntos de referencia usados regularmente en la práctica clínica. Para la obtención de los objetivos planteados, fueron evaluados 46 cadáveres formolizados de individuos de sexo masculino. Se obtuvieron los diámetros de las arterias carótidas común, externa (ACE) e interna (ACI), con el auxilio de un caliper digital. No hubo diferencias entre lados derecho e izquierdo, ni tampoco en los niveles estudiados. El nivel de bifurcación de la ACC fue medido en relación a puntos de reparos anatómicos relevantes en clínica (margen superior del cartílago tiroides, ángulo de la mandíbula y lóbulo del pabellón auricular), como también en relación al nivel vertebral. Nuestro estudio mostró que el margen superior del cartílago tiroides fue el punto de referencia más estable para inferir el nivel de bifurcación de la ACC. Es importante mencionar que, de todos los puntos de referencia estudiados, la vértebra cervical fue la única que mostró diferencias entre los lados, siendo más variable el nivel de bifurcación en el lado izquierdo.

In head and neck surgery, the common carotid arteries are important landmarks, defining dissection plane during radical neck surgeries. The objectives of the present study were to add information on the diameter of the carotid arteries and to correlate the common carotid artery (CCA) bifurcation level with important anatomical landmarks used regularly in clinical practice. Forty-six necks from male embalmed human cadavers were evaluated. The CCA as the external (ECA) and internal (ICA) carotid arteries diameters were studied with the aid of an electronic digital caliper. No differences were found between sides in any level studied. The CCA bifurcation level was measured in relation to clinically relevant anatomical landmarks (superior level of the thyroid cartilage, mandible angle and ear lobe) and the bifurcation level according to the cervical vertebra level was also investigated. Our study shows that the superior border of the thyroid cartilage was the most stable anatomical landmark for predicting the CCA bifurcation level. It is important to mention that from all the landmarks studied, the cervical vertebra was the only one to show differences between sides, with the left side bifurcation level more variable than the right side.

A cineangiocoronariographical study of the irrigation of the sinuatrial node and perinodal area in human hearts

Since the initial description of the sinuatrial node and its vascularization, numerous studies have shown the importance of the sinuatrial nodal branch (SNA). In this work, we examined the anatomy of this atrial branch using cineangiography. We reviewed the records of 100 cineangiocoronariographies done between October 1991 and November 1992 in the teaching hospital of the Faculty of Medicine of Triângulo Mineiro. The records of patients with artificial pacemakers or who had undergone cardiac surgery were not included. All the records showed left anterior oblique and right anterior oblique projections of both coronary arteries. In 65 por cento of the cases, the SNA occurred as a branch of the right coronary artery, and in 33 por cento it derived from the left coronary artery. Double irrigation of the sinuatrial area was seen in 1 por cento of the cases, and in 1 por cento of the cases the SNA originated from the aorta. In 76.9 por cento of the cases, the branch was of the medial anterior type and became less frequent in the distal part of the coronaries. There were no significant sex-related (χ2 = 0.0092), or racial (χ2 = 0.1241) differences. These finding were similar to those of studies based on anatomical or angiographic approaches. We conclude that the SNA can arise from any coronary artery, with no single, specific origin, and that there are no gender or race-related differences in this pattern.

Right retroesophageal subclavian artery

Purpose: The subclavian arteries can vary on their origin, course or length. One of the most common anatomical variations is the right subclavian artery originating as the last branch of the aortic arch. This artery is known as a retroesophageal right subclavian artery or "lusory artery". The right retroesophageal subclavian artery usually is described as not producing symptoms, being most discoveries coincidental. Nevertheless, it may be the site of formation of atherosclerotic plaque, inflammatory lesions or aneurysm. Case Report: The present study describes a case of right retroesophageal subclavian artery and discusses the findings according to their clinical and surgical implications. Conclusion: The anatomic and morphologic variations of the aortic arch and its branches are significant for diagnostic and surgical procedures in the thorax and neck. If a right retroesophageal subclavian artery is diagnosed during aortic arch repair, corrective surgery should be considered. Intensive care patients should be screened before long term placement of nasogastic tube, in order to avoid fistulization and fatal hemorrhage.

Brachial plexus variations in its formation and main branches

Purpose: The brachial plexus has a complex anatomical structure since its origin in the neck throughout its course in the axillary region. lt also has close relationship to important anatomic structures what makes it an easy target of a sort of variations and provides its clinicai and surgical importance. The aims of the present study were to describe the brachial plexus anatomical variations in origin and respective branches, and to correlate these variations with sex, color of the subjects and side of the body. Methods: Twenty-seven adult cadavers separated into sex and color had their brachial plexuses evaluated on the right and left sides. Results: Our results are extensive and describe a large number of variations, including some that have not been reported in the literature. Our results showed that the phrenic nerve had a complete origin from the plexus in 20 percent of the cases. In this way, a lesion of the brachial plexus roots could result in diaphragm palsy. It is not usual that the long thoracic nerve pierces the scalenus medius muscle but it occurred in 63 percent of our cases. Another observation was that the posterior cord was formed by the posterior divisions of the superior and middle trunks in 9 percent. In these cases, the axillary and the radial nerves may not receive fibers from C7 and C8, as usually described. Conclusion: Finally, the plexuses studied did not show that sex, color or side of the body had much if any influence upon the presence of variations.

Variaçöes da artéria axilar e seus ramos / Variations of the axilary artery and its branches

Este estudo objetivou descrever e qualificar as as variações da artéria axilar e medir seu calibre e de seus principais ramos, buscando relacionar o calibre arterial e a presença de variaçäo anatômica.Ointenta e quatro regiões axilares foram avaliadas com a obtençäo dos calibres arteriais, e classificadas segundo a presença de variações anatômicas.O número total de artérias variáveis foi de 40 (47,6 por cento) sendo que a variaçäo mais frequentemente encontrada foi a artéria circunflexa posterior originando-se como da artéria subescapular (67,5 por cento das variações).Outras variações menos frequentes foram observadas.Quanto ao calibre arterial, näo foram encontradas diferenças significativas quando comparados lados direito e esquerdo, bem como artéria axilar se apresenta mais comumente com seis ramos principais, tal qual descrita na literatura, porém em 32 por cento dos casos ela se mostrou com apenas cinco ramos. A presença de variaçäo da artéria axilar näo alterou o calibre dos seus principais ramos.